The aim of this project is to characterize the properties of voltage gated channels and synaptic transmission of hippocampal inhibitory neurons in the developing brain and how these properties impact hippocampal function under both physiological and pathological conditions. Although much is known about their neurochemistry, their role in the local circuits and the basic electrophysiological properties of of inhibitory interneurons, little is known about the specific ionic or ligand gated channels expressed on this highly divergent population of cells. A major part of our effort is to understand the ionic mechanisms which regulate the activity of these cells and how these mechanisms impact hippocampal function using patch clamp, immunohistochemical and molecular techniques. Our work over the past year has focused on particular populations of inhibitory neurons of the CA1 subfield. We have characterized the mechanisms of synaptic plasticity occurring on distinct population of inhibitory neuron and how changes in synaptic strength onto these neurons influences hippocampal function. In addition we have characterized the members of the Shaker family of potassium channels expressed on inhibitory neurons using both a combined electrophysiological and immunohistochemical approach. We have determined the roles of several voltage-gated currents in st. Oriens-alveus interneurons and their modulation by arachidonic acid and beta-adrenergic receptor activation. Furthermore we have investigated how "knock-out" of these channels by antisense oligonucleotides impact the physiological function of these cells.